This is a multidisciplinary project for investigation of methods of mechanical circulatory assistance for the failing heart leading to the development of clinically applicable techniques. The program will focus on development of assist devices and study of their physiologic effects and control. The devices to be investigated are the following: the intraaortic balloon pump for temporary left ventricular assistance; a prosthesis that replaces portions of the resected left ventricular myocardium, the dynamic prosthetic myocardium, and dynamic aortic patch, the U-shaped mechanical auxiliary ventricle, and a piezoelectric assist device, each designed for permanent circulatory support. An approach to replacement of excised left ventricular muscle will also be investigated. The effects of all of these methods on the hemostatic mechanism will be studied. Clinical investigations will include cardiac assistance in medically refractory cardiogenic shock utilizing the phase-shift balloon pump. Engineering studies on control and optimization of in-series assistance will involve theoretical and experimental investigations directed toward development of driving units for both temporary and permanent assist devices. Exploration of the effects of in-series circulatory assistance on myocardial ischemia will also be studied. BIBLIOGRAPHIC REFERENCES: Kiso, I., Baechler, C. A., Hamada, O., Mandell, G., Baba, H., and Kantrowitz, A.: An extravascular left ventricular assist device. Ann. Thorac. Surg. 21: 203, 1976. Schraut, W., Kiso, I., Freed, P., Baechler, C., Barnhart, M., Riddle, J., Mammen, E., Mandell, G., and Kantrowitz, A.: Permanent in-series cardiac assistance with the dynamic aortic patch: blood prosthesis interaction in long-term canine experiments. Surg. 79:193, 1976. Abstracted in Cardiology Digest, August 1976.